1. Field of the Invention
The present invention relates to a publication confirming method which estimates the date of issue of a publication, such as a newspaper, from contents of a part of the publication and provides information desired by a user and included in information appearing in the publication whose issuance date is estimated, and a publication information acquisition apparatus, publication information providing apparatus and database which accomplish the method.
2. Description of the Related Art
People well recognize newspapers available in the market as publications from which they can obtain various kinds of information. Some of subscribers of newspapers cut out those portions of newspapers in which information needed or interesting appears and file the clippings or scraps in scrapbooks or the like.
To ensure the reliability of matters written on such a newspaper scrap to be filed in a scrapbook or the like, it is important to clarify from which newspaper publishing company the newspaper was issued and the date of issue of the newspaper.
But it is not always the case that such a newspaper scrap filed in a scrapbook or the like is not cut out together with a portion which mentions the newspaper publishing company of the newspaper and the date of issue of the newspaper (normally, information at the topmost portion of a newspaper).
There may be a case where the name and the date of issue of a newspaper a piece of which is filed in a scrapbook or the like are handwritten in free space of the piece. Even in this case, the name and the date of issue of a newspaper may not always be handwritten. This often results in a lower reliability of newspaper scraps filed in a scrapbook or the like.
Newspaper scraps filed in a scrapbook or the like fade or become dirty with time. Even if such faded or dirty newspaper scraps filed in an original scrapbook are copied to create a new scrapbook, the copies obtained would not have a good image quality. This makes it insignificant to create the new scrapbook.
In view of this situation, some subscribers need to know the names and the dates of issue of newspapers pieces of which are filed in scrapbooks or the like. There may be some subscribers who need articles in newspapers which are specified by their names and issuance dates. Those people should acquire desired information by performing information retrieval. The following will describe some prior arts that relate to information retrieval.
Japanese Patent No. 2729356 proposes “an information retrieval method for extracting a topicality, with a computer process, from a database comprising a plurality of data elements each provided with time information and including information to which a keyword can be given, which method has a stage of determining a frequency of constant occurrence relating to a given keyword included in said data elements and defined as an estimated number of data elements given with time information in a unit time which includes said given keyword, constantly over a predetermined period of said time information; a stage of determining, as a start point of a topicality of said given keyword, a point at which a value obtained by subtracting said frequency of constant occurrence from the number of data elements given with time information in a unit time, which includes said given keyword, becomes maximum along an axis of said time information; a stage of determining, as an end point of said topicality of said given keyword, a point which is later than said start point of said topicality and at which the number of data elements given with time information in a unit time, which includes said given keyword, drops to a level of approximately said frequency of constant occurrence along an axis of said time information; a stage of providing a model beforehand as a function of a change in a frequency of topicality which monotonously decreases from said start point of said topicality to said end point of said topicality; a stage of determining a distance between said function given as said model beforehand and a graph of a change in said value obtained by subtracting said frequency of constant occurrence from the number of data elements given with time information for each unit time from said start point of said topicality to said end point of said topicality; and a stage of selecting said given keyword as a topic in response to a value of said distance relating to said given keyword being smaller than a certain threshold value”.
That is, the prior art information retrieval method is a scheme for presenting a keyword which allows a user who does not have a sufficient knowledge about a field relating to a document to be retrieved to reach a meaningful document or a document which is full of topics.
Unexamined Japanese Patent Application KOKAI Publication No. 2000-20538 proposes “an information retrieval method for retrieving information included in a plurality of documents from a database including said documents and source data of each document, which method includes a document specifying step of specifying a document from said database based on said source data; a topic word extracting step of extracting, as a topic word, a word appearing a predetermined number of times or more from words included in said document specified by said document specifying step; a topic word group identifying step of identifying a group of topic words commonly included in one document or a plurality of documents as a topic word group constituting a single topic; a group combination extracting step of extracting those two topic word groups in said topic word groups which have a common topic word, as one group combination; and a two-dimensional display step of displaying said topic word groups included in said group combination in a two-dimensional coordinate system determined by a first axis and a second axis, said first axis of said two-dimensional coordinate system representing a single source data item included in said source data while said second axis of said two-dimensional coordinate system represents said topic words”.
This prior art information retrieval method is designed to allow a user to easily take a general view of contents included in a database by presenting graphical display of the contents.
Unexamined Japanese Patent Application KOKAI Publication No. H10-289237 discloses a publication volume calculating apparatus which computes the publishing interval of publications using past history information of the publications and predicts the volume and the date of issue of the next publication to the recent publication. Further, Unexamined Japanese Patent Application KOKAI Publication No. H10-289237 discloses a technique of displaying the volumes of intervening publications based on the volumes of the first and last publications.
Unexamined Japanese Patent Application KOKAI Publication No. 2000-30145 discloses a newspaper output apparatus which extracts and outputs an article in a newspaper from the date of issue of the newspaper by referring to a database storing newspaper data.
Unexamined Japanese Patent Application KOKAI Publication No. 2001-76007 discloses a data managing method and system that store information which may be needed by a user in future on behalf of the user and provide the information when requested by the user as needed, and an apparatus which is used for the method and system.
Those prior arts however suffer the following problems.                (1) The technique disclosed in Japanese Patent No. 2729356 and the technique disclosed in Unexamined Japanese Patent Application KOKAI Publication No. 2000-20538 force a user to designate a keyword from contents of a scrap filed in a scrapbook or the like in order to search for newspaper information showing the publishing company and the date of issue of a newspaper to which the scrap belongs. Further, the user should decide whether the retrieved newspaper information is desired information or not. Those techniques are therefore troublesome and suffer a poor usability.        
While the technique disclosed in Unexamined Japanese Patent Application KOKAI Publication No. H10-289237 can acquire information relating to the volume, it cannot acquire information on the date of issue or the publishing company of a newspaper a piece of which is filed in a scrapbook or the like.
Because the technique disclosed in Unexamined Japanese Patent Application KOKAI Publication No. 2000-30145 requires an entry of the date of issue of a newspaper, it is necessary to acquire the date of issue of a desired newspaper beforehand somehow.